1. Field of the Invention
The present invention relates to an insertion device in which a rotor provided in an insertion section rotates, whereby press force is applied from a first projection of the rotor to a second projection of an assistance tool, and the assistance tool attached to the insertion section rotates together with the rotor. The present invention also relates to the assistance tool provided in the insertion device.
2. Description of the Related Art
International Publication No. 2013/038720 discloses a spiral unit (assistance tool) which is attached to an insertion section of an endoscope (insertion instrument). The spiral unit which is removably attached to the insertion section in a state to cover the insertion section from the outer peripheral side, and which includes a spiral fin spirally extends around a longitudinal axis. A rotor is provided in the insertion section, and the rotor is attached to a base portion of the insertion section in a state to be rotatable around the longitudinal axis. First projections (first rollers) are provided in the rotor, and second projections (second rollers) are provided in the spiral unit. The rotor rotates around the longitudinal axis by the transmission of driving force thereto, whereby press force is applied from each of the first projections to the corresponding second projection in a rotation direction of the rotor. Due to the application of the press force from each of the first projections to the corresponding second projection, the driving force is transmitted to the spiral unit, and the spiral unit rotates relative to the base portion around the longitudinal axis. Due to the rotation of the spiral unit around the longitudinal axis in a state where the spiral fin is pressed to an inner peripheral side, propulsive force toward a distal side or a proximal side is applied to the insertion section and the spiral unit.